19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
For the second period elements the correct increasing order of first ionization enthalpy is (NEET 2019)
The elements ‘X’, ‘Y’, and ‘Z’ form oxides which are acidic, basic, and amphoteric respectively. The correct order of their electronegativity is
Which one of the following arrangements represents the correct order of least negative to most negative electron gain enthalpy for C, Ca, Al, F and O? (NEET 2013)
Identify the wrong statement in the following (AIPMT 2012)
Amongst the following, select the element having highest ionisation enthalpy. (MHT CET 2014)
The electronic configuration of an element is 1s ,2s 2p ,3s 3p 3d ,4s 4p 4d ,5s 5p . From which group of the period table, it belongs ? (KCET 2012)
The stability of +1 oxidation state among Al, Ga, In and TI increases in the sequence (AIPMT 2015)
Which of the following pairs contain metalloid elements in the periodic table? (Kerala CEE 2017)
Which of the following oxides is most acidic in nature ? (NEET 2018)
Atomic number is equal to the…. A…. Here, ‘A’ refers to
Molybdenum metal is related to which block?
Which of the following compounds are formed when BCl₃ is treated with water ?
The geometry of a complex species can be understood from the knowledge of type of hybridisation of orbitals of central atom. The hybridisation of orbitals of central atom in [B(OH)₄]– and the geometry of the complex a…
When strongly heated, orthoboric acid leaves a residue of:
Which is the hardest compound of boron ?
The number of OH units directly linked to boron atoms in Na₂B₄O₇.10H₂O is:
o o Re d hot 100 C 160 C H BO X Y B O ; ¾¾¾® ¾¾¾® ¾¾¾® X and Y respectively are:
BF₃ is used as catalyst in several industrial processes due to its:
Identify X and Y in the following reaction. NaBH 140ºC C H Cl BCl NH Cl X Y + ¾¾¾¾® ¾¾¾¾®
Reactivity of borazole is higher than that of benzene because:
Which of the following statements about anhydrous alu- minium chloride is correct?
What happens when a mixture of cobalt oxide and borax is heated in a flame on a loop of platinum wire ?
In the structure of diborane
When aluminium hydroxide dissolves in NaOH solution, the product is:
Which of the following does not show similarity between boron and aluminium ?